Collet chucks and collet receptacles are widened clamping devices for rapid and force-fit tightening of tools having high accuracy. They usually have a chuck body with an internal taper, a collet insertable into the internal taper of the chuck body and a cap nut screwed to the chuck body. The collet contains a slit receptacle with an external taper adapted to the internal taper of the chuck body and a receptacle opening adjusted to the tool shank of the tool being clamped. The collet can be pressed into the internal taper of the chuck body by tightening the cap nut and the collet compressed to clamp the tool shank. Collets are designed so that they convert the axially running force acting via the cap nut to a holding force acting across the axis of rotation and therefore acting on the tool shank via their conical shape.
Such a collet chuck together with a collet is known from DE 87 17 516 U1. For non-slip transfer of torque between the chuck and the collet during machining, the collet has a pin on its end extending into the chuck with an axially symmetric external hexagon, accommodated in shape-mated fashion by an internal hexagon of the chuck. This type of collet chuck is used for the tightening of drills, milling cutters or other machining tools having a cylindrical tool shank. The tool shank is fastened by the clamping force generated via the cap nut. Use of such a collet is only possible with a chuck specially designed for it and in tools having a sufficiently long tool shank.